OBJECTIVETo provide prenatal diagnosis for two families affected with oculocutaneous albinism (OCA), in both of which only 1 pathogenic allele has been identified.

METHODSTo determine the clinical classification of OCA through DNA sequencing for TYR, P, TYRP1 and SLC45A2 genes in combination with phenotype analysis. Prenatal diagnosis was carried out by direct sequencing and intragenic SNPs family-based linkage analysis.

RESULTSIn the first family, only 1 heterozygous mutation c.1255C>T was found in the proband, which was inherited from her mother. Together with its clinical phenotype, the proband was suspected to have OCA2 Screening of amniotic fluid, however, has found no mutation. With family-based linkage analysis, the fetus was deemed to be an OCA2 carrier. In the second family, again only one heterozygous mutation c.1920_1949 del30bp and ins AACA was found in the proband, which was inherited from her father. Together with its clinical phenotype, the proband was suspected to have OCA2. Screening of amniotic fluid has revealed a heterozygous mutation c.1920_1949 del30bp and ins AACA. By family-based linkage analysis, the fetus was deemed to be an OCA2 carrier. Both fetuses had a normal phenotype at birth.

CONCLUSIONPrenatal genetic diagnosis has been provided for the first time for two families affected with OCA, in which only 1 pathogenic mutant allele was detected. The combined mutation detection and SNPs linkage analysis has turned out to be successful.